Dry kiln



Oct. 27, 1931.

H. l.. HENDERSON 1,829,139

DRYv KILN Filed May 3l, 1929 3 Sheets-Sheet l Oct. 27, 1931. H. L. HENDERSON DRY KILN 5 Sheets-Sheet 2 Filed May 3l', 1929 @CL 27, 1931. H. HENDERSON 1,829,139

DRY KILN Filed May 5l, 1929 3 Sheets-Sheet 3 vi 'f Ill NVENTOR.

TTORNE Ys,

Patented Oct. 27, i931 @PATENT OFFICE H'IRALM. L. BIENDEBSON"y OF ISYRACUSE, NEW YORK .DRY una? Application filed may 31,

This invention relates to a dry-kiln adapt` ed to be used more particularly for a drying lumber which has been stacked upon a su1t' able support within the kiln `in suchmanner i 'isto enable the heat to circulate between the several layers. l

The main object of the present invention is to effect a more thorough seasoning and ldrying of the lumber or other material within a l@ v:horter period of time than has heretofore been practiced.

In some instances heated air alone has been used for drying lumber, 'but this method requires a considerable period of time and results, in many instances, in merely drying the surface ef the lumber without penetrating to the interior of the several-pieces thereby.

causing more or less warping, checking or splitting of the lumber without thoroughly .29 drying and seasoning of the same.

gFurthermore, this hot air drying in some in stances has been supplemented by the intro'- duction of moisture such assteam to mingle with the heated air and to circulate therewith through the lumber stack for the purpose of effecting more thorough seasoning and'drying of the lumber, but in most instances with which I am familiar, the 'circulation of the moisture-laden air by an individual blower has been maintained in one direction only throughout the drying operation so that if a uni-direction al current is used, the drying operation must he continued for a longer period of time than would be required if the direcjn tion' of circulation werev intermittingly varied, resulting in excessive surface drying and consequent warping, checking and splitting of the lumber 'before the interiors of the several pieces has been thoroughly dried.' One ef the specific objects. therefore, ofthe present invention is to avoid these objectionable results by providing means whereby the direction of'flow of the air currents may be changed at suitable intervals so asto not only cause. a more thorough seasoning and drying of all parts of the lumber but also to expedite the seasoning and -drying operations so that a better quality of the finished product may be turned over in t'a shorter period of time 1929. Serial' No. 367,372.

andfwith considerably less carrying cost than has heretofore been practiced.

Other objects and uses relating to the speciic parts of this kiln will be brought out in the following description.

In the drawings Fig. 1 is a transverse vertical sectional view of a dry-kiln embodying the various features of my invention taken inthe plane of line 1 1, Fig. 2.

Fig. 2 is a longitudinal sectional. view of the same dry-kiln taken in the plane of line 2 2, Fig. l.

Fig. 3 is an enlarged detail sectional view of one end of the steam supply pipe for the steam distributing nozzles or blowers showing a portion of the handle for turning the pipe with .the nozzles thereon' for changing the direction of circulation of the steam and a1r.

'zo Fig. 4 is a detail sectional view taken in -the plane of line 4 4, Fig. 3.

Fig. 5 is an enlarged detail sectional view through the valve operating shaft taken in the plane of line 5 5, Fig. 2.

Fig. 6 is an enlarged detail sectional View through one of the steam nozzles and the adjacent portion ofthe steam pipe taken in the plane of line 6 6, Fig. E.

As illustrated, this dry-kiln comprises upse right side and end walls l and 2, and bottom, and top walls 3 and 4 forming a drying chamber 5, a heating chamber 6 underlying the drying chamber and partially separated therefrom by a horizontal partition wall 7, Figs. l and 2, and an air conduit 8 underlying the heating chamber and adapted to rest upon the bottom wall. 3 of the housing.

The partition 7 constitutes a floor extending from end to end of the drying chamber, and heating chamber but is relatively narrower transversely than the corresponding .width of said chambers to form air passages between its opposite longitudinal edges and opposite side wallsr ofthe housing as shown more clearly in Fig. 1. This oor 7 is mount- `ed uponsuitable cross-beams 9 which are supported at their ends upon the side walls l and are adapted 'to support a pair'of rails l0.

The rails l() extend lengthwise of and wit-ht0n in the housing adjacent the opposite longitudinal edges of the floor 7 for supporting a carriage 11 upon which the lumber or other material to lbe dried is stacked in such manner. as to allow circulation of the moistureladen air around and between the several layers.

The end walls of the drying chamber are provided with openings of suflicient size to permit the passage of the carriage 11 with the stack of lumber therethrough, said openings being normally closed by suitable doors 12' during the drying operation but may be opened at will to permit vthe carriage with the -lumber therein to be movedin-to and-out of the kiln. (See Fig. 2.)

A. The side walls l of the housing are 'provided with lupright air stacks or iues 13 arranged at suitable spaced intervals through 20`- the length of the side walls and extending from the lower end of the drying chamber 5 above the upper end thereof to communicate with the atmosphere.

The lower ends of these air stacks or flues 13 are provided with openings 14 connecting them with thev adjacent portions of the dryl ing chamber, the openings at each sidev being controlled by a set, of valves or dampers 15 which are mounted upon a suitable rock shaft l6 for simultaneous movement to and from their closed positions.

Each rock shaft 16 is j ournaled in suitable bearings 16 on the adjacent side wall1 to eX- tend through and beyond one of the end walls Where it is provided with a suitable hand crank 16 by which it may be rocked for opening and closing the corresponding series of dampers 15.

The outer end of each shaft is provided with a toothed rack 17 having its teethadapted to be engaged by a pawl or detent 18 which is spring pressed into engagement with the registrating tooth of the rack 17 by a spring 19 to hold the dampers 15 on that particular shaft in its adjusted position and thereby to closely control the volume of air passing through the openings 14 of the corresponding stacks 13 as may be required from time t0 time. (See Fig. 5.)

A heater 20 consisting, in this instance, of la series of steam pipe coils are suspended from the iioor 7 by hangers 21 within the heating chamber 6 or directly .beneath the .floor 7 and superposed drying chamber 5- to extendthe major portion of the length of said heating chamber'but relatively narrower than the same to form air passages: at opposite sides thereof connecting the heating chamber with the drying chamber.

The several sets of pipe coils of the heat-er 20,/are connected at their opposite ends to suitable pipe-headers 22 and 22, the header 22 being connected to a. steam supply pipe 23 leading from any available source of supply and providedl` with a. valve 23 adapted to be opened and closed at will, Whilethe header 22 is connected to a delivery pipe 24 leading to a steam condensing trap or drainage not shown, andmay be provided with anormally open valve 25 if desired.-

The air-conduit 8 is mounted on the bottom 3 of the heating chamber 6 directly beneath the heater 20 and extends from end to end of the housing to register Withair inlets 26 in opposite ends of said housing as shown in Fig. 2, for receivinglexternal fresh air.

The intermediate portionsof opposite sides of the conduit are provided at suitable intervals with additional air-inlet openings 2T to permit recirculation of the heated mois'- ture-laden air and (or) fresh air through the drying chamber when desired and in a man ner presently described.

The air-conduit'8 is also provided in itsl upper side with a series of outlet openings 28 in longitudinallyv spaced relation for permitting the fresh air or recirculated vapor to pass through the overlying heating and drying chambers for moistening and drying the lumber in the drying chamber, the oppositeside Walls of each outlet being upwardly y divergent to permit a relatively wide distribuion of the heated air into said drying cham- A tub-ularrock-shaft 29 is journaled in suitable bearings 3() centrally within the low- 'er portion of the conduit and extends the! major portion of the length thereof across all of the outlet 28, one end of said rock shaft being closed while the other end extends through the adjacent opening 26 and is connected by a coupling 31 to a steam or other fluid pressure supply pipe 32 leading to any available source of supply not shown, for supplying steam to the interior of the rock-shaft.

The intermediate portion of the tubular rock-shaft 29 is provided with a series of axially spaced ejector nozzles or blowers 823 projecting radially therefrom into the outlet openings 28 to rock with said shaft for re- 1 ceivingsteam therefrom and for discharging said steam in different directions and thereby changing the direction of circulation of the moisture-laden air through the drying chamber and lumber pile therein. (See Fig. '6.) A i These ejectors or blowers 33 are preferably of the multiple nozzle type in which the nozzles gradually increase in capacity from the rock-shaft outwardly to afford a gradually increasing range of distribution of the escaping steam and also to gradually reduce its speed of circulation through the drying chamber but without interrupting the free and continuous flow of the vapor.

In Fig. 6 one of the ejectors or blowers is shown as comprising a T-eoupling 3l connecting the adjacent ends of two sections of the rock-sha i" and provided with a radially projecting nipple upon which is mounted a seriesof connected outwardly tapered nozzles ,36 coaxial with the nipple 35 for receiving steamtherefrom.

rPhe diameters ofthe nipple 35 and nozzles 36 graduall increase .from the rock-shaft outwardly or the purpose previously described, the larger ends of the nozzles 36 being united to and supported by the smaller ends of the next adjacent nozzle and provided with air-inlet openings' 37 to allow the air Aor Vapor to be drawn thereinto by suctionl ment being limited by suitable stops 39 adapted to be engaged by the hand crank 38 as 25 shown in Fig. 4.

' The dry-kiln shown maybe used for crosspilin or end-piling compartment or progressive rying dependlng simplyupon the length of the kiln and number of heaters and steam 30.1listrib'utors used, it being understood that when a progressive or stage drying is required the kiln will be made of s'uiiicient length topermit the movement of the lumber lcarrier'to diii'erent positions therein and that '35 'n each different position the lumber may be subjected tod different degrees of temperature' and (or) different degrees of humidity.

A baiile plate 40 is suspended from the top wall 4 of the dry-kiln-intc the upper portion 40- ofthe dryingchamber 5 to extend from end to end of said drying chamber substantially midway between the opposite side walls of the kiln, as shown in Fig. 1, to prevent direct circulation of the heated vapor over' the top of the lumber stack A and thereby to cause a more even distribution of the heated vapor between'the several layers of the stack.

`Operation Y rier 11 with thestack of lumber to be seasoned and dried thereon is moved along the Y track 10 into the drying chamber 5 qafter which both of the doors are closed -to retain the-heat in said chamber.

l The steam-controlling valve 23 may then be opened to admit steam to the heater coils 20 for heating the surrounding air and per'- 4mittingI the same to rise into the drying cham-- ber for circulationbetween the several layers of lumber on the carrier 11.

v Thesteam may be admitted to the tubular rock-shaft 29` and' discharged through the several ejector nozzles or blowers 33 into v the heatingchamber 6 and thence into the When one of the doors 12 is opened the car-- drying chamber to mingle with the heated air -to accelerate circulation of the moisturev lloaden air between the several layers of lum- This introduction of the several jetsv of steam into the drying chamber causes the fresh air to be drawn rom the outside of the kiln through the openings 26 into the conduit 8 and thence throughithe outlets 28 to mingle with the steam so that the mixture of aira-nd steam will be forcibl circulated upwardly into the drying cham er and between the several layers of lumber, the moistened vapor serving to soften the texture of the lumber and thereby to liberate the inherent moisture and sap therefrom, it being understood that the steam-supply pipe 32 will be provided with a suitable controlling valve, not shown, for regulating the quantity of the steam admitted to the drying chamber.

It is al'so to be understood that the moisture-laden air when delivered to the drying chamber will be pre-heated'by the heating coils 20 thereby increasing the humidity of the vapor for moisture and permitting the moisture and sap in the lumber to be carried 0H' continuously by the circulation thereof between the several layers of lumber.

The direction of circulation of the vapor throughy the drying chamber may be varied at will by simply rocking the tubular shaft 29 with-theiblowers 33 thereon to different positions about theaXis thereof through the medium of the hand-crank 38 thus permitting a. relatively wide range of distribution of the vapor in dierent directions between the several layers of lumber in said chamber.

-That'is, when the blowers 33 are shifted to one extreme position as shown by full line in Fig. 1, the current of moisture-laden air will be directed upwardly across the correspondin side of the lumber stack -A and thence t rough the several layers of lumber to return at the opposite side-of said stack, the lateral deflection of the upwardly circulating currents of vapor between the several layers of lumber being aided by the use of the baille plate 40.

On the other hand, if the blowers 33 are shifted to the other extreme ition as shown by dotted lines in Fig. 1, t e direction of circulation of the heated vapor will be re versed, it being understood that if the blowers are adjustedto an intermediate position, the circulationof the heated vapor will -be directed across both sides of the lumber stack and will find its own direction of return..

It is evident from the foregoing descrip- 1 tion, that the adjustment of the blowers 33 justing the blowers from one position to the other.

For example; if circulation of the vapor through the drying chamber is to be maintained in one direction, the dampers I54 in one of the side walls of the kiln may be closed and those in the opposite side walls may be opened to which conditions the blowers 33 would be adjusted to direct the circulation therefrom toward the side of the wall having the closed dampers to enable the vapor to pass upwardly between the closed side and adjacent side of the lumber stack and thence transversely between the several layers of said stack and return through the opened dampers to escape through the adjacent flues i3,

Again, if the vapor is -to be re-circulated through 'the drying chamber as may be required in some conditions of the lumber 'the dampers 15in both of the side walls of the kiln will be closed thus allowing the vapor to pass upwardly from the blowers 33 into the drying chamber at one side of the lumber stack'and thence transversely between 'the layers of the lumber and return at the opp'oy site side of the stack to the interior air-conduit 8 through the adjacent openings 27 for recirculation of the same vapor togethery with such quantities of fresh air as may be drawn into the conduit 8 through the openings 26. y

This same uni-directional circulation or recirculation of the heated air or vapor through the drying chamber and lumber stack mayy take place without introducing steam or extra moisture through the ejector nozzles or blowers 33 by simply shutting 0E the supply of steam to the tubular shaft 29, it being understood that when the uni-directional circulation is reojuifed` one or the other of the dampers l5 will be opened more or less to regulate the rapidity of' circulation and that when 'both dempers are closed, the re-circulation will follow.

It is, therefore, evident that the lumber in the sa-me compartment may be dried in different stages or according to the condition of the lumber by regulating the quantity of steam delivered through the blowers 33 or by shutting off the supply of steam to said blowers and relying primarily upon the heat produced by the heater coils 20'and admission of fresh air into the dying chamber through the air-conduit 8.

- It is also evident that by extending the length of the dry-kiln and duplicating the heaters and steam distributing blowers along the kiln at different positions, the unseasoned lumber may be subjected tothe circulation of moisture-laden air with the lumber-supporting carriage in one position and then moving the carriage with the lumber thereon to another position where the lumber may '55 be subjected to thecirculation of air with a reduced moisture content and ,finally to another position where the steam supply for moistening purposes may be shut ofi' and the lumber subjected to heated air alone with such moisture content as may be contained in the atmosphere admitted to the air-conduit 8, thus producing what may be termed a progress or stage drying ofthe lumber.

What I claim is:

1. A dry-kiln having a heating chamber, a drying chamber above the heating chamber, a-heater within the heating chamber, a fresh air conduit below the heating chamber having communication with the external air and provided with an outlet discharging int-o and through theheating chamber and means for projecting steam through the outlet for humidifying the air in transit from said conduit through the heating chamber and thence upwardly through the drying chamber, said means being movable in opposite directions to different angles for changing its direction ofcirculation of the air and steam through said drying chamber.

2. A dryskiln having a drying chamber, means in the lower part of the said drying chamber for supporting the material to be dried. a heating chamber below the drying chamber, a heater within the heating chamber, anair conduit below the heating chamber having an air inlet communicating with the drying chamber and anl outlet discharging into the heating chamber and means for discharging steam through the outlet into the heating chamber and drying chamber for humidifying the air and to cause a return flow of the humidilied air from the drying chamber into said conduit through the inlet. said means including a steam pipe rockable about its axis andrprovided with a plurality 'of radialsteam exits in its upper side.

terior of the conduit upwardly through said outlet and into the heating chamber and drying chamber for humidifyingthe air and circulating it through the drying chamber, said means including a plurality of steam nozzles tiltable to different angles for changing the direction of circulation of the humidified air.

4. A dry-kiln having a. drying chamber provided with an air outlet in one of its side walls near the lower end thereof, an air stack Lezama connected to said air outlet and extended upwardly therefrom above the drying chamber, means within the dry-kiln for supporting the material to be dried, a heating chamber below the drying chamber, a heater within the heating chamber, an air conduit beneath the heating chamber andl provided with an inlet communicating with theexternal air, said air conduit having an outlet discharging into the heating chamber and drying chamber andI means for projecting steam through theoutlet of the air conduit toward the wall of the drying chamber opposite the outletpof said drying chamber for humidifying the air and causing it to circulate upwardly at one side of the material to be dried opposite of the outlet of the drying chamber and thence around and through the material to be ,dried and outwardly through the outlet of the drying chamber to escape 4 through said stack, said means including a steam pipe rockable about its axis and provided with a plurality of radial discharge nozzles. i.:

5. A dry-kiln having a drying chamber, a heater for heating theair in the drying chamber, an air. conduit beneath the drying chamberhaving an air inlet communicating with the external air and provided with an upwardly discharging outlet, and means for directing a iiuid vunder pressure through ,the outlet for circulating the heated air through they drying chamber, said directing means being adjustable to change the direction of flow of the pressure fluid and thereby to change the direction of the circulation of'" the heated air through the drying chamber.

6. A dry-kiln having aodrying chamber, means for supporting the material to be dried 40 within said chamber, a heater below the drying chamber for heating the air therein, an air conduit beneath. the heater havingfan air inlet communicating Withthe drying chamber and provided with an outlet in its upper side to permit the -re :irculation of air from the air conduit to thedrying chamber and return to the air conduit, and steam reand return to the air conduit, and means for directing Steam from the interior of the 'air conduit through its outlet for humidiyin the air and for re-circulatin the humidie air through the drying cham er and return to the air conduit, said means including a steam nozzle movable to diierent angles for changing the direction of circulation of the steam and air` through the drying chamber.

8'. A dry-kiln having a drying chamber, means for supporting the material to be dried within said chamber, a heater belowthe drying chamber for heatin the\ air therein, an air conduit beneath the eater having an air inlet communicating with the drying chamber and provided with an outlet in its u per side to permit the re-circulation of air rom the air conduit to the drying chamber and return to the4 air conduit, and means for directing steam from the interior of the air conduit through its outlet for humidifying the air and for re-circulating the humidiiied air through the drying chamber and return to the air conduit, said steam directing means being adjustable to diii'erent positions for changing direction of circulation of the air through the drying chamber.

In witness whereof I have hereunto set my hand this 1st day Aof May, 1929.

' HIRAM L. HENDERSON.

ceiving means for directing steam from the interior of the a1r conduit through its outlet 50 .to expedite the re-circulation of the air,.sai d.

steam-receiving means including aA steam` pipe having an upwardly projectin nozzle movable in opposite directions to4 'fferent angles for chan ing the direction of ow of the steam an air through the drying chamber. c

7. A dry-kiln havin "a dryin chamber means for supportinggthe matrial to be dried within said chamber, a heater below the drying chamber for heating the air therein, an air conduit beneath the heater having an air inlet communicating with the drying chamber and provided with an outlet in its .uppersside to permit the rez-circulation' of air f i from the air conduit to the drying chamber 

